POS1383 ANTI-TIF-1-Y DERMATOMYOSITIS IN OVERLAP WITH GREAT VESSEL VASCULITIS: A CASE REPORT
Authors: F. D’alessandro, F. Fattorini, L. Carli, M. Cazzato, M. Mosca
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Dermatomyositis (DM) are systemic autoimmune diseases that are part of Idiopathic inflammatory myopathies. The peak incidence is at the age of 50–60 years. The DM-related autoantibodies Anti-TIF-1γ are found in DM associated with aggressive skin lesions. However, in adults above the age of 40, anti-TIF-1γ antibodies are strongly associated with malignancy <sup>[1]</sup>. <h3>Objectives</h3> The aim of the work is to illustrate a difficult management of anti-TIF1-y dermatomyositis in overlap with great vessel vasculitis. <h3>Methods</h3> In January 2022 a 79-year-old woman suffering only from arterial hypertension was beginning to develop heliotropic and occipital rash, initially interpreted as an allergic reaction to an antihypertensive drug and treated with antihistamines without clinical benefit. Over the following weeks rhinolalia, mixed dysphagia, and Gottron's papules developed simultaneously. She performed a laryngoscopy excluding a deficit of the vocal cords. In the suspicion of esophageal diverticulosis performed X-ray with gastrografin, showing no alterations of the esophageal tract. The picture was related to a major depressive episode and antidepressant therapy was initiated. In May 2022 worsening of muscle symptoms led the patient to go to the hospital again, with subsequent transfer to our rheumatological department. She was cachectic, dysphagic, with hypostenia (MMT8 35/80) and skin rash typical for DM. Therefore, some investigations were ordered, showing: - High titer positivity for anti-TIF1y, PL-12, SSA-Ro52 - Significant retention in the oro-pharyngeal region at swallowing study - Edema of the pelvic girdle muscles, compatible with a picture of myositis in the phase of activity on magnetic resonance - Increase CPK and inflammation indices in blood chemistry tests Hence, a diagnosis of DM was performed. Because the recent onset of the disease, and for the association described in the literature between Anti-TIF1y and neoplastic disease, further investigations were required to exclude the paraneoplastic nature of the clinical picture. While waiting to conclude the investigations, therapy with intravenous pulse of glucocorticoids has been started (1.5mg/kg) with progressive decalage. Despite a predominantly cutaneous improvement, the symptoms progressively worsened by reducing the steroid below the threshold dose of 1mg/kg, with the appearance of a new cutaneous flare. During hospitalization, the patient showed a gradual increase in inflammation indices, associated with pancytopenia. After excluding an underlying hematological cause, FDG-PET was performed. It showed uptake of the drug in the ascending and arch of the thoracic aorta, and both subclavian arteries. In order to exclude infectious causes of aortitis, in-depth examinations were performed, with negative results (HIV, syphilis). <h3>Results</h3> The finding of vascular uptake despite therapy with intravenous pulse of glucocorticoids, the absence of infections and the clinical symptoms led us to diagnose dermatomyositis overlapping with vasculitis of the great vessels. <h3>Conclusion</h3> Our case represents the first description of overlap between these two diseases within 5 months of clinical onset. Therefore, we decided to initiate therapy with intravenous pulse of glucocorticoids (2mg/kg) with progressive tapering, associating it with IntraVenous ImmunoGlobulin (IVIG) and periodic intravenous immunosuppressive therapy with Cyclophosphamide (CFX), since the efficacy of these drugs was demonstrated both on systemic vasculitis and on DM. After the first days of combination therapy, the patient showed marked improvement in the muscles and skin, regaining the ability to eat and being able to resume daily activities (MMT8 70/80). <h3>Reference</h3> [1]De Vooght J, Vulsteke JB, De Haes P, Bossuyt X, Lories R, De Langhe E. Anti-TIF1-γ autoantibodies: warning lights of a tumour autoantigen. Rheumatology (Oxford). 2020 Mar 1;59(3):469-477. doi: 10.1093/rheumatology/kez572. PMID: 31883334. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.